I'm having an issue unlocking a chest in the cemetery of Tortuga Bay (Pirates)
There's a puzzle where you need to slide the corresponding color tiles into the correct spots. The problem is the gate isn't unlocking after it's done.
This shows the tiles beforehand:

This shows the tiles after they've been placed:

I've even attempted it with the other two tiles just to confirm I wasn't mistaking the color but it doesn't seem to work.
Has anyone encountered this?